Mycolic acid patterns of some species of Mycobacterium

Souza

Mem. Inst. Oswaldo Cruz

1998

Section: Resultssupporting

confidence: 64%

Identification of Mycobacteria by Thin Layer Chromatographic Analysis of Mycolic Acids and Conventional Biochemical Method: Four Years of Experience

Souza

Mem. Inst. Oswaldo Cruz

1998

Progress in Lipid Research

“…The characteristic MA patterns of a large number of mycobacteria were collated using TLC and GC-MS of the meromycolates produced by thermal fragmentation [40,41]. Although much of the work characterising MA has been carried out by mass spectrometry or GC-MS of meromycolates, HPLC has also been used to provide distinctive profiles of MA.…”

Section: Structural Properties Of Mycolic Acids Of Mycobacterium Specmentioning

confidence: 99%

“…Mycolic acids occur in a distinct group of Gram-positive bacteria, classified in the suborder of Corynebacterineae, including the genera Mycobacterium, Nocardia, Rhodococcus and Corynebacterium, mentioned here in the order in which they contain large-and-complex to small-andsimple mycolic acids. In Corynebacterium the mycolic acids are smallest (C 28 -C 40 ) and seem only to provide a beneficial, but not life-essential permeability barrier for the exchange of nutrients and antibiotics over the cell wall [2]. In contrast, Mycobacterium species are fully dependent for growth and survival in vitro and in vivo on their mycolic acids, which are the largest (C 60 -C 90 ) in nature [3,4].…”

Section: Introductionmentioning

confidence: 99%

Towards understanding the functional diversity of cell wall mycolic acids of Mycobacterium tuberculosis

Verschoor

Baird

Grooten

2012

Mycolic acids constitute the waxy layer of the outer cell wall of Mycobacterium spp and a few other genera. They are diverse in structure, providing a unique chromatographic foot-print for almost each of the more than seventy Mycobacterium species. Although mainly esterified to cell wall arabinogalactan, trehalose or glucose, some free mycolic acid is secreted during in vitro growth of M. tuberculosis. In M. tuberculosis, alpha-, keto-and methoxy-mycolic acids are the main classes, each differing in their ability to attract neutrophils, induce foamy macrophages or adopt an antigenic structure for antibody recognition. Of interest is their particular relationship to cholesterol, discovered by their ability to attract cholesterol, to bind Amphotericin B or to be recognised by monoclonal antibodies that cross-react with cholesterol. The structural elements that determine this diverse functionality include the carboxylic acid in the mycolic motif, as well as the nature and stereochemistry of the two functional groups in the merochain. The functional diversity of mycolic acid classes implies that much information may be contained in the selective expression and secretion of mycolic acids to establish tuberculosis after infection of the host. Their cholesteroid nature may relate to how they utilize host cholesterol for their persistent survival.

“…For routine work, the simplified techniques of Becker et al (46) (239). Mycolic acid methyl esters can be identified on thin-layer chromatograms because they are not removed when plates are subsequently washed with methanol-water (5:2 [vol/vol]) (393,398). The presence or absence of mycolic acid methyl esters is one of the major tests used in presumptive identification to the genus level (Table 3).…”

Section: Laboratory Diagnosismentioning

confidence: 99%

The medically important aerobic actinomycetes: epidemiology and microbiology

1994

The aerobic actinomycetes are soil-inhabiting microorganisms that occur worldwide. In 1888, Nocard first recognized the pathogenic potential of this group of microorganisms. Since then, several aerobic actinomycetes have been a major source of interest for the commercial drug industry and have proved to be extremely useful microorganisms for producing novel antimicrobial agents. They have also been well known as potential veterinary pathogens affecting many different animal species. The medically important aerobic actinomycetes may cause significant morbidity and mortality, in particular in highly susceptible severely immunocompromised patients, including transplant recipients and patients infected with human immunodeficiency virus. However, the diagnosis of these infections may be difficult, and effective antimicrobial therapy may be complicated by antimicrobial resistance. The taxonomy of these microorganisms has been problematic. In recent revisions of their classification, new pathogenic species have been recognized. The development of additional and more reliable diagnostic tests and of a standardized method for antimicrobial susceptibility testing and the application of molecular techniques for the diagnosis and subtyping of these microorganisms are needed to better diagnose and treat infected patients and to identify effective control measures for these unusual pathogens. We review the epidemiology and microbiology of the major medically important aerobic actinomycetes.